Bonding pattern for disposable absorbent articles

ABSTRACT

An article includes a first web and second web underlying the first web. Each of the first and second webs includes first and second end regions and first and second side regions. The first web includes a precursor web having a pattern of discrete substantially columnar protruded extensions extending only from a first surface of the precursor web, each of the protruded extensions having a sidewall defining an open proximal portion and a closed distal portion. The article further includes a bonding pattern adhering together at least one of the first end regions of the first and second webs and the second end regions of the first and second webs. The bonding pattern includes a plurality of discrete bonding points and a sized spacing between each adjacent bonding point sufficient to have inscribed therein a circle having a diameter of about 1 mm to about 12 mm.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of prior co-pendingInternational Application No. PCT/US11/53609 filed on Sep. 28, 2011,designating the U.S., which claims the benefit of U.S. ProvisionalApplication No. 61/388,733 filed Oct. 1, 2010.

FIELD OF THE INVENTION

The invention relates to an article having a bonding pattern for bondingtogether at least two webs of material. More particularly, thisinvention relates to an article having a bonding pattern for bondingtogether two webs of material such that tearing of the webs duringnormal use of the article can be prevented.

BACKGROUND OF THE INVENTION

Absorbent articles such as sanitary napkins, pantiliners, tampons,absorbent interlabial devices, disposable diapers, incontinenceproducts, and bandages are designed to absorb and retain liquid andother discharges from the human body and to prevent body and clothingsoiling. In the manufacture of absorbent articles, it is generallynecessary to bond the components that will form the absorbent articletogether in order to form the finished product. For example, topsheetmaterials can be bonded to a secondary layer, for example, a secondarytopsheet material, to provide added strength and reinforcement to thetopsheet material.

Some web materials, such as low cost soft and silky tactile webmaterials (for example, for use as topsheet materials), have weakmaterial strength in the cross direction. It has been observed that whentypical bonding patterns are used to bond together such web materials,tearing occurs during use between bonding points. While, increasing thenumber of bonding points bonding the web materials together woulddecrease the amount of unbounded material that is susceptible to thetearing problem, such an increase would undesirably increase thestiffness of the material, making it less comfortable and less desirableto a consumer using a product having the bonded webs. Thus, thereremains a desire and need in the art to develop an article havingsufficient bonding between the web materials, particularly when using alow cost web material with weak material strength in the crossdirection, so as to prevent tearing of the web material during use,without undesirably increasing the stiffness of the web material.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the disclosure, an article includesa first web and second web underlying the first web, wherein the firstand second webs each include first and second end regions and first andsecond side regions. The first web includes a precursor web having apattern of discrete generally columnar protruded extensions extendingonly from a first surface of the precursor material, each of theprotruded extensions having a sidewall defining an open proximal portionand a closed distal portion. The article further includes a bondingpattern adhering together at least one of the first end regions of thefirst and second webs and the second end regions of the first and secondwebs. The bonding pattern includes a plurality of discrete bondingpoints and a sized spacing between each adjacent bonding pointsufficient to have inscribed therein a circle having a diameter of about1 mm to about 12 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a bonding pattern in accordancewith an embodiment of the disclosure;

FIG. 2 is a schematic illustration of a bonding pattern in accordancewith another embodiment of the disclosure;

FIG. 3 is a schematic illustration of a prior art bonding pattern forwhich topsheet tearing is observed;

FIG. 4 is a schematic illustration of a prior art bonding pattern forwhich topsheet tearing is observed; and

FIG. 5 is a schematic illustration of a first web material suitable foruse in an embodiment of the disclosure.

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter that is regarded as thepresent invention, it is believed that the invention will be more fullyunderstood from the following description taken in conjunction with theaccompanying drawings. Some of the figures may have been simplified bythe omission of selected elements for the purpose of more clearlyshowing other elements. Such omissions of elements in some figures arenot necessarily indicative of the presence or absence of particularelements in any of the exemplary embodiments, except as may beexplicitly delineated in the corresponding written description. None ofthe drawings are necessarily to scale.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein is an article having first and second web materials,portions of which are bonded together using a bonding pattern thatovercomes one or more of the aforementioned shortcomings of the priorart. For example, the article in accordance with embodiments of thedisclosure advantageously includes a bonding pattern which can preventtearing of the first web material during use of the article withoutundesirably affecting the tactile feel of the webs.

An article in accordance with an embodiment of the disclosure includes afirst web and a second web underlying the first web. The first webincludes a precursor web having a pattern of discrete substantiallycolumnar protruded extensions. The protruded extension can extend, forexample, from a first surface of the first web, which is disposedopposite the surface of the first web which contacts the second web. Theprotruded extensions each have a sidewall defining an open proximalportion and a closed distal portion. In various embodiments, first webcan include macroapertures to render the first web fluid permeable. Thefirst and second webs each include first and second end regions andfirst and second side regions disposed between the first and second endregions. The article includes a bonding pattern, which adheres togetherat least one of the first end regions of the first and second webs andthe second end regions of the first and second webs. The bonding patternincludes a plurality of discrete bonding points and a sized spacingbetween each adjacent bonding point, which is sufficient to haveinscribed therein a circle having a diameter of about 1 mm to about 12mm.

The first end regions of the first and second webs can be about 10% toabout 30% of the total area of the article. For example, the first endregions of the first and second webs can be about 25% of the totalsurface area of the article. The second end regions of the first andsecond web can be about 10% to about 30% of the total area of thearticle. For example, the second end regions of the first and secondwebs can be about 25% of the total surface area of the article. Thefirst and second webs further include first and second side regions. Thefirst side regions can be about 10% to about 30% of the total area ofthe article, and the second side regions can be about 10% to about 30%of the total area of the article. For example, the first and second sideregions can each be about 25% of the total area of the article.

First Web

The first web materials suitable for use in the article in accordancewith an embodiment of the disclosure are advantageously lower costmaterials than typical topsheet materials, such as for example, thetopsheet material commercially available as the soft dry weave coverused in the ALWAYS ULTRATHIN pads (Procter & Gamble). However, such webmaterials tend to stick to the skin of the user during use and have lowyield points, which can result in tearing of the web between bondingpoints when such web materials are incorporated into an absorbentarticle. For example, as compared to the commercially available soft dryweave cover used in the ALWAYS ULTRATHIN pads, the first web materialexhibits significantly increased stick to skin and has decreased yieldstrength.

Suitable first web materials are described in U.S. Pat. No. 7,521,588and U.S. Patent Publication Nos. 2010/0230857, 2010/0230858,2010/0230866, and 2010/0230867, the disclosures of which areincorporated herein in their entireties. The first web includes aprecursor web, which can include, for example, a plurality of discreteprotruded extensions extending only from a first surface of theprecursor web. The first web can further include macroapertures. In oneembodiment, the first web includes macroapertures and does not includediscrete protruded extensions.

Examples of films suitable for use as the precursor web include films oflow density polyethylene (LDPE), linear low-density polyethylene(LLDPE), and blends of linear low-density polyethylene and low densitypolyethylene (LDPE/LLDPE). The precursor material can have a thicknessof about 10 microns to about 25 microns. For example, suitable precursorweb thicknesses include about 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25 microns. One material found suitable for use asthe precursor web is DOWLEX 2045A polyethylene resin, available from TheDow Chemical Company, Midland, Mich., USA. A film of this materialhaving a thickness of 20 microns can have a tensile yield of at least 12MPa; an ultimate tensile of at least 53 MPa; an ultimate elongation ofat least 635%; and a tensile modulus (2% Secant) of at least 210 MPa(each of the above measures determined according to ASTM D 882).

The protruded extensions have sidewalls defining an open proximalportion and a closed distal portion. The discrete protruded elements canform hair-like fibrils that extend from a first surface of the web. Thediscrete protruded elements impart a soft feel to the web material,making it more desirable for use in an absorbent article, andparticularly for use as a topsheet material in an absorbent article. Theprotruded extensions can be formed integral with the film, and can beformed by permanent local plastic deformation of film. The protrudedextensions have a height measured from a minimum amplitude betweenadjacent protruded extensions to a maximum amplitude at the closeddistal portion. The protruded extensions can have a diameter, which fora generally cylindrical structure is the outside diameter at a lateralcross-section. By “lateral” is meant generally parallel to the plane ofthe first surface of the web. For non-uniform lateral cross-sections,and/or non-cylindrical structures, the diameter is measured as theaverage lateral cross-sectional dimension at ½ the height of theprotruded extension. Thus, for each protruded extensions, an aspectratio, defined as height/diameter, can be determined. The protrudedextensions can have an aspect ratio of at least 0.5. Other suitableaspect ratios include, for example, about 0.5, 1, 1.5, 2, 2.5, and 3.

The diameter of protruded extensions can remain constant or can decreasewith increasing amplitude (amplitude increases to a maximum at theclosed distal end). For example, the diameter, or average lateralcross-sectional dimension, of protruded extensions can be a maximum atthe proximal portion and the lateral cross-sectional dimension steadilydecreases to distal end. The protruded extensions can have an averagecross-section diameter of about 50 microns to about 130 microns, about60 microns to about 120 microns, about 70 microns to about 110 microns,and about 80 microns to about 100 microns. Other suitable averagecross-section diameters include about 50, 60, 70, 80, 90, 100, 110, 120,and 130 microns.

The area density of the protruded extensions, which is the number ofprotruded extensions per unit area of the first surface of the web, canbe optimized for use in absorbent articles. In general, thecenter-to-center spacing can be optimized for adequate tactileimpression, while at the same time minimizing fiber-to-fiber entrapmentof fluid. Currently, it is believed that a center-to-center spacing ofabout 100 microns to 250 microns is optimal for use in sanitary napkins.Minimizing entrapment of menses between fibers improves the surfacecleanliness of the sanitary napkin, which, in turn improves thecleanliness and skin health of the wearer.

The first web can further include a plurality of apertures to allow thefirst web to be liquid permeable. For example, the apertures can bemacroapertures which are formed by a multiplicity of interconnectingmembers, such as fiber like elements, that are interconnected to oneanother to define a continuous first surface of the web. Themacroapertures can have any suitable shape. For example, themacroapertures can polygon-shaped. In one embodiment, the macroapertureshave a hexagon shape. The macroapertures can have a diameter in a rangeof about 300 microns to about 1000 microns, about 400 microns to about900 microns, about 500 microns to about 800 microns, or about 600microns to about 700 microns. In one embodiment, the first web includesmacroapertures and discrete protruded extensions. The apertures canextend from the first surface of the web to a second surface of the webso as to extend in an opposite direction as the protruded extensions andthe discrete protruded extensions can be disposed only the first surfaceof the web. Referring to FIG. 5, in one embodiment, the first web 40 caninclude macroapertures 46 with discrete protruded extensions 48extending only from a top 42 (i.e., first) surface of the web. Thesidewalls 44 of the macroapertures 46 remain free from discreteprotruded extensions 48.

Second Web

The second web can be any suitable web material. For example, the secondweb can be a secondary topsheet material, which can impart addedstrength and structural reinforcement to the first web material. Thesecond web can include, for example, absorptive materials. In oneembodiment, the second web includes a nonwoven layer formed by a mix ofsynthetic fibers and cellulose to impart absorptive properties to thesecond web material. An example of a suitable secondary topsheetmaterial for use as the second web is REXCELL PTCX 077 (Rexcell AB).

Bonding Pattern

Referring to FIG. 1, the bonding pattern 18 adheres together at leastone of the first end regions 10 of the first and second webs and thesecond end regions 12 of the first and second webs. The bonding pattern18 includes a plurality of discrete bonding points 20. The bondingpatterning 18 further includes a sized spacing 22 between adjacentbonding points sufficient to have inscribed therein a circle having adiameter of about 1 mm to about 12 mm. The circle is inscribed so as tobe tangent to the adjacent bonding points. Other suitable diametersinclude about 2 mm to about 10 mm, about 3 mm to about 10 mm, and about4 mm to about 8 mm. For example, the sized spacing can be sufficient tohave inscribed therein a circle having a diameter of about 1 mm, 2 mm, 3mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, and 12 mm. As usedherein, “adjacent bonding points” refers to two bonding points, whichcan be connected by a straight line that does not intersect or otherwisetouch another bonding point. Adjacent bonding points are also disposedin the same end region (the first end region 10 or the second end region12). Such a sized spacing advantageously provides a bonding pattern 18in which the first and second webs are sufficiently adhered togethersuch that the first web does not exhibit tearing during use of thearticle, while allowing the first and second webs to remain sufficientlysoft and flexible so that the article remains soft and silky to thetouch.

FIGS. 3 and 4 illustrate prior art bonding patterns. Common features ofthe bonding pattern 18 of FIGS. 3 and 4 are labeled with commonreference numbers from FIGS. 1 and 2 having a leading “1.” The prior artarticles include first and second end regions 110 and 112, respectively,having a bonding pattern 118 adhering together the first and secondwebs. The bonding patter 118 includes a plurality of bonding points 120.However, the sized spacing 122 between adjacent bonding points 120 canvary drastically between adjacent bonding points. It has been observedthat when using such bonding patterns 118, absorbent articles having thefirst web material disclosed herein exhibit tearing during use. Such aprior art bonding pattern 118 has larger spacing 122 between some of theadjacent bonding points, which allows larger unbounded areas of thefirst web that are susceptible to tearing. A comparison of FIGS. 3 and 4to FIG. 1 illustrates that the bonding pattern 18 in accordance with theembodiment of the disclosure has a sized spacing 22 designed to decreasethe size of the unbounded areas of the first web, while not resulting inan increase in the number of bonding points 20 which would render thearticle stiff to the touch and undesirable for use.

The bonding pattern 18 can cover about 10% to about 20%, about 15% toabout 20%, about 12% to about 18%, or about 14% to about 16% of thetotal surface area of the first or second end regions 10 and 12,respectively, of the first and second webs. For example, the bondingpattern 18 can cover about 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%,19%, or 20% of the total surface area of the first and second endregions 10 and 12, respectively.

The bonding pattern 18 can adhere together only the first end regions 10of the first and second webs. Alternatively, the bonding pattern 18 canadhere together only the second end regions 12 of the first and secondwebs. In yet another embodiment, the bonding pattern 18 can adheretogether both the first and second end regions 10 and 12, respectively,of the first and second webs. It has been observed that tearing of thefirst web during use most often occurs in the back end of the article.Thus, for articles that do not have defined front and back ends, it canbe advantageous to provide the bonding pattern 18 in both the first andsecond end regions 12 of the article.

The article can further include a second bonding pattern 24 that adherestogether at least one of the first sides regions 14 of the first andsecond webs and the second side regions 16 of the first and second webs.The second bonding pattern 24 includes a plurality of discrete secondbonding points 26. The center-to-center spacing between each adjacentsecond bonding point 26 preferably is about 1 mm to about 3 mm, about1.5 mm to about 2 mm, about 1.2 mm to about 1.8 mm, and about 1.1 mm, toabout 1.5 mm. Other suitable center-to-center spacings include about 1,1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5,2.6, 2.7, 2.8, 2.9, and 3 mm.

Referring to FIG. 2, the second bonding pattern 24 can have theplurality of second bonding points 26 arranged in a series oflongitudinal lines 32. The spacing between adjacent longitudinal linescan be about 1 mm to about 5 mm, about 2 mm to about 4 mm, about 2 mm toabout 3 mm, or about 3 mm to about 5 mm. Other suitable spacings betweenadjacent longitudinal lines can be about 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5,and 5 mm.

The second bonding pattern 24 can cover about 10% to about 20%, about15% to about 20%, about 12% to about 18%, or about 14% to about 16% ofthe total surface area of the first or second side regions 14 or 16,respectively, of the first and second webs. For example, the secondbonding pattern 24 can cover about 10%, 11%, 12%, 13%, 14%, 15%, 16%,17%, 18%, 19%, or 20% of the total surface area of the first and secondside regions 14 and 16, respectively. In one embodiment, the secondbonding pattern 24 can be arranged on the side regions such that acenter portion 30 of the article remains free of bonding points. Forexample, the second bonding pattern 24 can bond portions of the firstand second side regions 14 and 16, respectively, of the first and secondwebs, leaving a center portion 30 of the article free of second bondingpoints 26. In yet another embodiment, the second bonding pattern 24 canbond only the first side region 14 or only the second side region 16 ofthe first and second webs.

The bonding points 20 in the first and second end regions 10 and 12,respectively, of the article and the second bonding points 26 can haveany suitable shape including, for example, circular, elliptical,triangular, rectangular, and combinations thereof. These bonding pointscan have a diameter of about 1 mm to about 2 mm, about 1.1 mm to about1.8 mm, about 1.4 mm to about 1.6 mm, and about 1.6 mm to about 2 mm.Other suitable bonding point diameters include, for example, about 1,1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2 mm.

These bonding points can be formed by any known means. For example,these bonding points can be formed using adhesive or by melt fusing thefirst and second webs at discrete bonding points. Suitable examples ofmethods of bonding web materials can be found in U.S. Pat. Nos.7,056,404 and 4,854,984.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. An article comprising: front end and a back end;a first web comprising a precursor web having a pattern of discretesubstantially columnar protruded extensions extending only from a firstsurface of the precursor web, each of the protruded extensions having asidewall defining an open proximal portion and a closed distal portion,wherein the first web comprises macroapertures having a diameter in therange of 600 microns to 1000 microns, a second web comprising syntheticfibers and cellulose underlying the first web, wherein each of the firstand second webs comprises first and second end regions and first andsecond side regions; and a first bonding pattern adhering together thesecond end regions of the first and second webs corresponding to theback end of the article, the first bonding pattern comprising aplurality of discrete bonding points and a sized spacing between eachadjacent bonding point such that a circle having a diameter greater than3 mm may be inscribed without contacting two or more bonding points anda circle having a diameter greater than 12 mm may not be inscribedwithout contacting two or more bonding points, wherein the first bondingpattern exists solely in the back end of the article.
 2. The article ofclaim 1, wherein the first end regions of the first and second webs isabout 10% to about 30% of a total area of the article.
 3. The article ofclaim 1, wherein the second end regions of the first and second webs isabout 10% to about 30% of the total area of the article.
 4. The articleof claim 1, wherein the bonding points comprise an adhesive.
 5. Thearticle of claim 1, wherein the bonding points have a shape selectedfrom the group consisting of a circle, an ellipse, a rectangle, atriangle, and combinations thereof.
 6. The article of claim 1, whereinthe bonding points have a diameter in a range of about 1 mm to about 2mm.
 7. The article of claim 1, wherein the second web is an absorbentstructure.
 8. The article of claim 1, wherein the bonding pattern coversabout 10% to about 20% of the total surface area of the first or secondend regions of the first and second webs.
 9. The article of claim 1,further comprising a second bonding pattern adhering together at leastone of the first side regions of the first and second webs and thesecond side regions of the first and second webs, the second bondingpattern comprising a plurality of discrete second bonding points and acenter-to-center spacing between each adjacent second bonding point ofabout 1 mm to about 3 mm.
 10. The article of claim 9, wherein theplurality of second bonding points are arranged in a series oflongitudinal lines.
 11. The article of claim 10, wherein the spacingbetween adjacent longitudinal lines is about 1 mm to about 5 mm.
 12. Thearticle of claim 9, wherein the second bonding points have a shapeselected from the group consisting of a circle, an ellipse, a rectangle,a triangle, and combinations thereof.
 13. The article of claim 9,wherein the second bonding points have a diameter of about 1 mm to about2 mm.
 14. The article of claim 9, wherein the second bonding patternadheres together only one of the first side regions of the first andsecond webs or the second side regions of the first and second webs. 15.The article of claim 9, wherein the second bonding pattern adherestogether both the first side regions of the first and second webs andthe second side regions of the first and second webs, a first portion ofthe second bonding pattern adheres together the first side regions ofthe first and second webs, a second portion of the second bondingpattern adheres together the second side regions of the first and secondwebs.
 16. The article of claim 9, wherein the bonding pattern coversabout 10% to about 20% of the total surface area of the first or secondside regions of the first and second webs.